Mutiny in the stands and mediocrity on the pitch. When even the Capital One Cup descends into acrimony and defeat, Rafa Benitez must wonder if he will ever turn around this disaffected, unhappy club that he currently calls home.

The Chelsea interim coach will have considered defeat to Queen's Park Rangers at Stamford Bridge a week ago as deeply regrettable, but things rapidly went downhill tonight. In the semi-final first leg of the good old League Cup they slumped to Swansea who scored two goals that were gifted to them by two schoolboy errors from the defender Branislav Ivanovic.

Ten years ago, Swansea City were in such a bad state that they were fighting for their lives in the fourth tier and changed hands for £1. That was the same year that Roman Abramovich began his colossal investment in Chelsea, £1bn and counting, and tonight at possibly the lowest ebb in the Russian's ownership the two stories collided in dramatic fashion.

Life at Stamford Bridge is, at the moment, surreal to say the least. There is a manager who is subject to hostility, as intense as ever tonight from the home fans. Then there were the calls for Demba Ba to be brought on, just one game into his Chelsea career. And to top it all there is the Frank Lampard, who spent much of the night running up and down the touchline applauding the fans taking his side in the contract stand-off.

Oh, and the chairman Bruce Buck, who made a pre-match presentation on the pitch, was booed for his role – as the fans see it – in the refusal to extend Lampard's stay at the club beyond the summer. And this was before they went and lost their second home game in the space of eight days.

In the midst of it all, Benitez was batting on bravely. He insisted that his team had played well and although some of their football was excellent, his plea to look beyond the result fundamentally misunderstood how life at Chelsea operates. The decision to appoint him was based on the conviction that – however unpopular – he would bring the club success and results like tonight were not part of the plan.

The achievement of Swansea and their manager Michael Laudrup should not be overlooked on a monumental night for the club. They have won at Anfield and the Emirates this season but tonight was as good as either of those wins with the peerless Michu opening the scoring and his useful sidekick Danny Graham, a second-half substitute, nicking the second in added-time at the end.

Bravo, Laudrup, who is 90 minutes away from Swansea's first-ever major cup final if they can negotiate the second leg at the Liberty Stadium in two weeks' time when away goals will count double only after extra-time is played. The Dane is unflappable and although this team is a talented ensemble there is no-one quite like the lethal Michu who scores goals in the fashion that Chelsea wish Fernando Torres would.

Oh dear, Fernando, another night in which he sunk beneath the waves, hiding behind the shoulders of defenders and failing to affect the game. Ba achieved more in the nine minutes he played than Torres did in the 81 minutes in which he was involved, including two headers and a late goal from the new boy that were incorrectly ruled offside by referee Anthony Taylor.

Where do Chelsea go from here? To Stoke, of all places, on Saturday where Benitez will hope that the roller-coaster form his team have endured in the last week stabilises. He surely cannot start with Torres away from home against a side as physical as Tony Pulis' outfit, which was presumably the rationale for playing the Spanish striker.

Laudrup said that, in all, Chelsea created just four clear chances to score, yet in the first half they dominated possession completely. The little band of brothers who operate behind Torres – Juan Mata, Oscar and Eden Hazard – looked lively and there was no better move all half than the sequence of passes that played in Ramires on 11 minutes for a disappointing stab at goal.

That was not the only chance that was missed. Hazard teed up Mata on 26 minutes and he hit his shot straight at the goalkeeper. The Spain international struck another across the face of goal. Even Cesar Azpilicueta, yet to score for his new club had a crack at goal. The expectation was that one would go in at some point.

The first Swansea goal was presented to them by Ivanovic, who took the ball from goalkeeper Ross Turnbull and turned straight into trouble. The enterprising Jonathan de Guzman, who played well against Arsenal in the FA Cup on Sunday, stole the ball away from Ivanovic and it broke left to Michu.

Even from that position, the Swansea striker's task was by no mean simple. Gary Cahill had recovered and was moving into position to block the direct route to goal. No problem for the goal machine from Oviedo, who switched the ball from his right foot to his left, away from Cahill and found the space to lift a shot quickly past Turnbull.

After that, Laudrup's team parked the bus resolutely and Benitez's players were obliged to pick their way through the roadblock. The calls for Ba became more insistent and when finally he came on there were cheers – as much, it seemed, for the departure of Torres.

Chelsea besieged Swansea in the closing stages of the match. Then Ivanovic went into malfunction mode again, passing the ball short to Turnbull and allowing Graham to steal in and finish neatly for the second.

After that, Ba scored a goal when Lampard flicked on Azpilicueta's cross that should have stood but was ruled out for offside. Replays showed that decision was incorrect. Less forgivable was a decision by Taylor to book Ba, presumably for diving, as he challenged for a ball with goalkeeper Gerhard Tremmel. Ba deserved better on his home debut.

Certainly, the goal Ba scored that was disallowed was legitimate, and the two headers that followed, marked him out as an excellent option for Chelsea. The way things are going, Benitez may feel he has no option but to play his new signing. Certainly they cannot afford to lose to Stoke City on Saturday.

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